JP4746907B2 - Planetary gear reducer - Google Patents

Description

  The present invention relates to a planetary gear reduction device that includes an internal gear and an external gear that is internally meshed with the internal gear, and that extracts a relative rotational component between the internal gear and the external gear as an output.

  A planetary gear reduction device that includes an internal gear and an external gear that meshes internally with the internal gear and that extracts a relative rotational component between the internal gear and the external gear as an output is widely used.

  For example, Patent Document 1 discloses a planetary gear reduction device as shown in FIG.

  This planetary gear reduction device 10 includes an input shaft 12, an eccentric body 14, two external gears 16 (16A, 16B), an internal gear 18, a relative rotation extraction mechanism K, and first and second support flanges 50, 60 is provided as a main component.

  Each external gear 16 includes an internal pin hole 30 that passes through the external gear 16. The relative rotation take-out mechanism K is fitted into the inner pin hole 30, the first support flange 50 and the second support flange 60, and is loosely fitted into the inner pin hole 30 via an inner roller 42. The pin 40 and the inner roller 42 are configured. A step 40 a is formed on the inner pin 40 and restricts the positions of the first and second support flanges 50 and 60.

  When the input shaft 12 is rotated by a motor (not shown), the eccentric body 14 rotates integrally with the input shaft 12. Since the outer periphery of the eccentric body 14 is eccentric with respect to the axis of the input shaft 12, the external gear 16 mounted on the outer periphery of the eccentric body 14 swings once when the input shaft 12 rotates once. As a result, the external gear 16 rotates relative to the internal gear 18 by an amount corresponding to the difference in the number of teeth of the two gears 18 and 16. This relative rotation is taken out to the first and second support flanges 50 and 60 via the inner pin hole 30, the inner roller 42 and the inner pin 40 of the relative rotation take-out mechanism K.

  The swing component of the external gear 16 is absorbed by loose fitting of the inner pin hole 30 and the inner roller 42 and the inner roller 42 and the inner pin 40 in the relative rotation extraction mechanism K. As a result, a reduction ratio corresponding to (the number of teeth difference between the internal gear 18 and the external gear 16) / (the number of teeth of the external gear 16) can be realized.

  This planetary gear reduction device 10 has an advantage of being compact and capable of obtaining a high reduction ratio, and is used in various fields.

JP 2000-65162 A

  In the field of this kind of planetary gear reduction device, particularly when used as a reduction device for driving an industrial robot, a very high rotational accuracy is required. In particular, it is important to eliminate the backlash and increase the positioning accuracy of the working part of the robot. When adjustment is necessary after use, it is desirable that the adjustment can be performed easily and effectively. .

  Furthermore, as a feature when used in industrial robots, not only the driving force of a motor or the like is transmitted in the forward direction, but it is also transmitted in a complicated manner while repeating forward and reverse rotation, and further acceleration / deceleration and stop. The As a result, the power transmission part (member) in the planetary gear speed reduction device is more susceptible to stress than in the case of continuous rotation in only one direction. The In this respect, it is not preferable that the insertion portion of the inner pin in the first and second support flange portions is narrowed to form the “step portion”.

  Further, the first support flange for taking out the relative rotation may be integrated with the second support flange on the opposite side in the axial direction via an inner pin due to the mechanism of the planetary gear speed reducer. In such a case, if there is even a manufacturing error in the formation of the step portion of the support flange or the inner pin, the error becomes an assembly error, and rattling and backlash increase.

  In order to prevent this, it may be possible to manufacture all the members such as the support flange and the inner pin with higher accuracy, but it is very expensive to further improve the accuracy of the members that were originally manufactured with high accuracy. Therefore, it is not appropriate as a real problem. In particular, in the case of the conventional example, since the step portion for position regulation is formed by “remaining” portions obtained by processing the inner pin from both sides, it is very difficult to ensure dimensional accuracy.

  Therefore, the present invention has been proposed to solve these problems, and it is an object of the present invention to provide a planetary gear reduction device that has less backlash and rattling and that can be easily adjusted afterwards. .

The present invention relates to a planetary gear reduction device that includes an internal gear and an external gear that is internally meshed with the internal gear, and that extracts a relative rotational component between the internal gear and the external gear as an output. A first support flange disposed on one side in the axial direction of the toothed gear via a first bearing; a second support flange disposed on the other side in the axial direction of the external gear via a second bearing; An inner pin formed integrally with the first support flange and extending to the second support flange through the external gear, and a bolt capable of press-contacting the inner pin and the second support flange; The above-mentioned problem is solved by sandwiching a shim between the second support flange and the inner pin in the axial direction and press-contacting the inner pin and the second support flange via the bolt. It is a thing.

  In the present invention, the inner pin is integrally formed with the first support flange (as a single component), and further, the inner pin and the second support flange are press-contacted by a bolt, thereby forming the first core that is the core of the speed reduction device. The preload adjustment of the support flange, the inner pin, the second support flange, and the second bearing portion can be easily and accurately performed. Further, if necessary, the preload adjustment of the first support flange and the first bearing can be performed at the same time with some structural improvements. In addition, since adjustment is possible by changing the thickness of the shim, a manufacturing error of a component can be absorbed by sandwiching a shim having a required thickness at a required location among a plurality of inner pins. As a result, it is not necessary to increase the manufacturing accuracy of the parts more than necessary, and it is possible to suppress an increase in cost, and it is possible to effectively prevent the occurrence of rattling and an increase in backlash due to poor preload adjustment.

  According to the present invention, it is possible to provide a planetary gear reduction device that can easily and accurately perform a preload adjustment operation for members constituting the core of the device.

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is a longitudinal sectional view corresponding to FIG. 5 showing a planetary gear reduction device according to an example of an embodiment of the present invention.

  The planetary gear reduction device 110 includes an input shaft 112, an eccentric body 114 (114A to 114C), three external gears 116 (116A to 116C), an internal gear 118, and a relative rotation extraction mechanism K1 as main components. Prepare. Further, in order to support the inner pin 140 that is one of the components of the relative rotation extraction mechanism K1 in a cantilevered manner, the first support flange 150 and the second support flange 160 are provided on both axial sides of the external gear 116. Prepare.

  The input shaft 112 is rotatably supported by a third bearing 152 and a fourth bearing 162 that are in contact with the first and second support flanges 150 and 160, respectively. The input shaft 112 includes a hollow portion 112A having a large diameter at the center (hollow structure) and can be connected to a motor shaft (not shown) via a spline 112B. The motor shaft and the spline 112B may be connected via a gear.

  The eccentric body 114 is formed integrally with the input shaft 112. The eccentric body 114 includes three eccentric portions 114A to 114C. The centers OeA to OeC of the outer circumferences of the eccentric portions 114A to 114C are eccentric by ΔE with respect to the axis Oi of the input shaft 112, respectively. Further, the eccentric phases of the eccentric portions 114A to 114C are shifted from each other by 120 degrees.

  The three external gears 116 (116A to 116C) are rotatably mounted on the eccentric portions 114A to 114C of the eccentric body 114 via rollers 117 (117A to 117C), respectively. The roller 117 is positioned in the axial direction by a third bearing 152 and a fourth bearing 162 that support the input shaft 112. The reason why three external gears 116 are arranged in parallel in the axial direction is to increase the transmission capacity. Each external gear 116 includes an internal pin hole 130 that passes through the external gear 116.

  The internal gear 118 is constituted by an internal gear body 118B integrated with the casing 111 of the planetary gear reduction device 110 and a roller-shaped pin constituting the internal gear 118A.

  The first support flange 150 and the second support flange 160 are rotatably supported by the casing 111 by a first bearing 154 and a second bearing 164, respectively. An external machine (not shown) that is a drive target can be connected to the first support flange 150 using a bolt or the like (not shown). Further, the first support flange 150 is integrally provided with an inner pin 140 (as a part of itself). Specifically, the first support flange 150 and the inner pin 140 are integrally formed by forging.

  The outer rings 154A and 164A of the first bearing 154 and the second bearing 164 are fixed to the casing 111, respectively. On the other hand, the inner ring 154B of the first bearing is fixed to the first support flange 150, and the inner ring 164B of the second bearing is fixed to the second support flange 160, respectively. Here, “fixed” is a concept including integrally molding.

  The contact surfaces of the outer rings 154A, 164A with the balls (rolling elements) 154C, 164C are the axial external gear 116 side of the respective bearings 154, 164 (the second bearing 164 side if the first bearing 154 is used as a reference). If the second bearing 164 is used as a reference, the arcs are substantially the same as the arcs of the balls 154C and 164C, and rises inward in the radial direction. More specifically, the outer ring 164A of the second bearing 164 has a contact surface C3 in contact with the ball 164C. The thickness H of the outer ring 164C in the contact surface C3 in the radial direction is formed to be thickest on the external gear 116 side (first bearing 154 side) (H1) and thinnest on the anti-external gear 116 side ( H2).

  On the other hand, the outer ring 154A of the first bearing 154 has the same configuration in the axial direction symmetry. That is, the outer rings 154A and 164A restrict the movement of the balls 154C and 164C toward the external gear.

  On the contrary, the shape of the contact surface of each inner ring 154B, 164B with the ball 154C, 164C is a shape that swells outward in the radial direction toward the anti-external gear side. That is, the inner rings 154B and 164B regulate the movement of the balls 154C and 164C toward the non-external gear side.

  The relative rotation take-out mechanism K1 includes the inner pin 140, the inner roller 142, and an inner pin hole 130 formed in the external gear 116. An inner roller 142 is rotatably mounted on the outer periphery of each inner pin 140, and the inner pin hole 130 and the inner pin 140 are configured to transmit power via the inner roller 142.

  Here, a connection structure between the inner pin 140 and the second support flange 160 will be described with reference to FIG. FIG. 2 is an enlarged view of an arrow II part in FIG.

  As shown in FIG. 2, the second support flange 160 has a recess 146 into which the inner pin 140 can be fitted. The inner pin 140 is fitted in the recess 146, and a shim 170 is sandwiched between the inner pin tip surface 140A and the recess bottom surface 146A. In this embodiment, two shims 170 are sandwiched, but the number and thickness of the shims 170 can be adjusted as necessary. A wide variety of adjustments can be made by preparing shims 170 having a thickness of about 2 to 3 types and combining them appropriately.

  The shim 170 has a flat donut shape, and has a hole 170 </ b> A through which a bolt 180 connecting the inner pin 140 and the second support flange 160 can be inserted at the center.

  Returning to FIG. 1, the first support flange 150 formed integrally with the inner pin 140 in the present embodiment is subjected to a carburizing quenching and tempering process (hardening process) to increase the overall surface hardness. Yes. Further, induction hardening is applied to the portion C2 that functions as the inner shaft of the bearing. A nitriding treatment may be performed as the hardening treatment.

  Reference numeral 185 in FIG. 1 is an enclosing port for enclosing grease, and reference numeral 187 is a seal member.

  Next, the operation of the planetary gear reduction device 110 will be described.

  When the input shaft 112 is rotated by rotation of a motor shaft (not shown), the eccentric body 114 integrated with the input shaft 112 is rotated. Since the outer periphery of the eccentric body 114 is eccentric by ΔE with respect to the axis Oi of the input shaft 112, the three external gears 116 each have a phase difference of 120 degrees via the roller 117 due to the rotation of the eccentric body 114. It swings and rotates while being inscribed in the internal gear 118. In this example, since the internal gear 118 is integrated with the casing 111, when the external gear 116 swings and rotates once by the input shaft 112 rotating once, the external gear 116 is rotated by the internal gear 116. Rotate (spin) relative to 118 by an amount corresponding to the difference in the number of teeth of both gears 116 and 118.

  This relative rotation is taken out to the first and second support flanges 150 and 160 through the inner pin hole 130, the inner roller 142 and the inner pin 140 constituting the relative rotation take-out mechanism K1. The swing component of the external gear 116 is absorbed by loose fitting of the inner pin hole 130 and the inner roller 142 and the inner roller 142 and the inner pin 140 in the relative rotation extraction mechanism K1. As a result, a reduction ratio corresponding to (the number of teeth difference between the internal gear 118 and the external gear 116) / (the number of teeth of the external gear 116) can be realized in only one stage.

  In the planetary gear reduction device 110 according to this embodiment, the first support flange 150 and the external machine (not shown) to be driven are connected using a bolt or the like (not shown). An external machine can be driven through the first support flange 150 side. It is also possible to fix the first support flange 150 and use the casing 111 itself as an output member (so-called frame rotation structure).

  Further, by sandwiching a shim 170 having various thicknesses between the inner pin 140 and the second support flange 160, it is possible to adjust the axial length L1 (see FIG. 1) of the planetary gear reduction device 110. Become. Adjusting this length L1 means adjusting the assembly of the planetary gear speed reduction device 100 as a whole, and consequently adjusting the radial direction. If the shim 170 to be sandwiched is made thinner, the length L1 is shortened, but as described above, the balls 154C and 164C in the outer rings 154A and 164A of the first bearing 154 and the second bearing 164, respectively. And the contact surface with the balls 154C and 164C in the inner rings 154B and 164B toward the anti-external gear side. Due to the shape that swells outward in the radial direction, the positions of the balls 154C and 164C in the radial direction are determined at the same time, and the position in the axial direction is also determined without difficulty. That is, the preloads of the contact points (ball 154C and outer ring 154A, ball 154C and inner ring 154B, ball 164C and outer ring 164A, ball 164C and inner ring 164B) are defined at the same position, and the first bearing 154 and the second bearing 164 are respectively It can be assembled without causing contact pressure more than necessary. Accordingly, the positions of the internal teeth 118A, the external gear 116, the internal roller 142, and the like are also assembled at predetermined positions, and as a result, the radial play during rotation tends to be reduced.

  The shim 170 does not always need to be sandwiched between all the inner pins 140 and the second support flange 160, and the length L1 varies due to manufacturing errors of the inner pins 140 and the second support flange 160. Can be sandwiched to correct. Therefore, as long as the shim 170 is inserted into any one of the inner pins 140, the thickness and the number of the shims 170 sandwiched between the inner pins 140, and further selection such as not sandwiching are free. .

  In this embodiment, the shim can be easily replaced by removing the bolt 180 and removing the second support flange 160. Therefore, if it becomes necessary to readjust over time due to the use of the device, etc. Adjustment work can be performed easily.

  Furthermore, in this embodiment, the preload of the first bearing 154 and the second bearing 164 can be adjusted simultaneously only by adjusting the thickness of the shim 170, so that the adjustment work is compared with the case where each is adjusted independently. This time can also be shortened.

  Further, as in the present embodiment, when the inner pin 140 and the first support flange 150 are integrally configured (as a single member) and also function as the inner ring 154B of the first bearing 154, a single unit is used. Even if it is a single member, the required characteristics differ depending on each part. That is, in the portion C1 that functions as the original inner pin 140 for extracting the relative rotational component, it is particularly required to ensure wear resistance and dimensional accuracy in addition to the slidability. On the other hand, in part C2 that functions as an inner ring of the bearing, in addition to slidability, rolling fatigue resistance is particularly required.

  Therefore, in the present embodiment, the entire first support flange 150 (inner pin 140) is once subjected to carburizing and quenching and tempering within a range not exceeding the transformation point of the member, and further, a portion C2 (functioning as an inner ring of the bearing) The surface that is also in contact with the oil seal 187) is subjected to induction hardening. The portion C1 functioning as the inner pin 140 is not performed because it is distorted and needs to be reworked if induction hardening is performed after processing with high accuracy. In addition, in this embodiment, since this part C1 can be processed by a straight process on a structure, ensuring of high dimensional accuracy is easy.

  Thereby, the site | part C1 can ensure slidability, abrasion resistance, and high dimensional accuracy, and the site | part C2 can ensure the property excellent in slidability and rolling fatigue resistance.

  The “transformation point” means a temperature at which the crystal structure of the member changes during heating (processing) and austenite starts to be generated.

  Further, the above-described curing treatment is not limited to carburizing quenching and tempering treatment and induction quenching treatment, and can be appropriately changed in consideration of required hardness and cost such as nitriding treatment and polishing.

  Next, a planetary gear reduction device 310 will be described with reference to FIG. 3 as another embodiment. In addition, about the part which is the same as that of the planetary gear speed reducer 110 mentioned above or similar here, only the same code | symbol is attached | subjected to the last 2 digits, and duplication description is abbreviate | omitted.

  Compared to the planetary gear reduction device 110 described above, the planetary gear reduction device 310 is characterized by a screw portion N3 (a screw portion to which a bolt 380 connecting the first support flange 350 and the second support flange 360 can be screwed. ) Is in a different position. That is, the portion where the inner pin 340 is inserted into the recess 346B provided in the second support flange 360, that is, the portion other than the axial position P3 corresponding to the recess 346B of the inner pin 340 (the inner pin A feature is that a threaded portion N3 is provided on at least one of 340 and the first support flange 350). For convenience, the description of the bolt (380) on the upper side of the figure is omitted.

  With such a configuration, the stress acting on the inner pin is dispersed by avoiding the overlap between the stress generated in the screw part and the position of the fitting part (the part where the bending stress is maximized) caused by the load applied to the speed reducer. In addition, the durability of the bolt 380 can be increased.

  Next, a planetary gear reduction device 410 will be described with reference to FIG. 4 as another embodiment. Again, repeated explanation is omitted.

  Also in this planetary gear reduction device 410, the feature is in the position of the threaded portion N4. Here, the screw portion N4 is provided at the first support flange 450 (corresponding to the axial position). With such a configuration, the bolt 480 that is used inevitably becomes long, and the screw portion and the head of the bolt are further separated, so that the internal force coefficient of the bolt can be increased, and the effect that the bolt is difficult to break is exhibited. The In this case as well, as described in the planetary gear reduction device 310, the axial position P4 corresponding to the concave portion 446B of the second support flange 460 is not provided with a threaded portion, so that durability against shearing force is ensured. Has been.

  In the example of the above embodiment, an example in which three external gears are provided in the axial direction is shown. Since the present invention supports the inner pins on both ends, a particularly remarkable effect is obtained when a plurality of external gears are arranged side by side in the axial direction. However, the application of the present invention is not necessarily limited to the case where three or more external gears are arranged in parallel as described above. For example, although not shown, only two external gears are provided. The present invention can also be applied to an equipped reduction gear, and can also be similarly applied to a reduction gear having only one external gear.

  Moreover, in the example of the said embodiment, the structure by which the inner roller was covered around the inner pin was shown. In the present invention, the presence of the inner roller is not always essential.

  Of course, it is applied in the field of industrial robots that require extremely high precision in the radial direction of rattling and backlash adjustment. The present invention can be widely applied in the field of planetary gear speed reducers that are used in a usage mode in which accuracy is required and rattling is likely to occur.

Whole side sectional drawing of planetary gear speed reducer 110 which is one of the embodiments of the present invention. Enlarged view of arrow II in Fig. 1 Whole side sectional drawing of planetary gear reduction gear 310 which is one of other embodiments of the present invention. Whole side sectional drawing of planetary gear speed reducer 410 which is one of the other embodiments of the present invention. Whole side sectional view of a conventional planetary gear reduction device

Explanation of symbols

DESCRIPTION OF SYMBOLS 110 ... Planetary gear reduction device 112 ... Input shaft 114 ... Eccentric body 116 ... External gear 118 ... Internal gear K1 ... Relative rotation taking-out mechanism 130 ... Inner pin hole 140 ... Inner pin 142 ... Inner roller 146 ... Recess 150 ... First Support flange (output shaft)
152, 154, 162, 164 ... Bearing 160 ... Second support flange 170 ... Shim 180 ... Bolt

Claims (9)

In a planetary gear reduction device comprising an internal gear and an external gear internally meshing with the internal gear, and taking out a relative rotational component between the internal gear and the external gear as an output,
A first support flange disposed on one side in the axial direction of the external gear via a first bearing;
A second support flange disposed via a second bearing on the other axial side of the external gear;
An inner pin formed integrally with the first support flange and extending through the external gear to the second support flange;
A bolt capable of press-contacting the inner pin and the second support flange, and
A planetary gear reduction device, wherein a shim is sandwiched between the second support flange and the inner pin in the axial direction, and the inner pin and the second support flange are pressed into contact with each other via the bolt. In claim 1,
At least a part of the internal gear is formed in the casing;
The second bearing, the outer ring is fixed to the front mute pacing, the inner ring is fixed to the second support flanges, characterized in that the rolling element is fastened to the outer ring and the inner ring by a fastening force of the bolt Planetary gear speed reducer. In claim 1 or 2,
The contact surface of the outer ring of the second bearing with the rolling element is formed so as to rise radially inward toward the first bearing side, and
A planetary gear reduction device characterized in that a contact surface of the inner ring of the second bearing with the rolling element is formed so as to swell outward in the radial direction toward the side opposite to the first bearing. In claim 3,
Furthermore, the contact surface of the outer ring of the first bearing with the rolling element is formed so as to rise radially inward toward the second bearing side, and
A planetary gear reduction device characterized in that a contact surface of the inner ring of the first bearing with the rolling element is formed so as to rise outward in the radial direction toward the second bearing side. In any one of Claims 1 thru | or 4,
A concave portion is formed in the second support flange, and the inner pin is fitted in the concave portion. In claim 5,
A threaded portion that can be screwed with the bolt is formed on at least one of the inner pin and the first support flange, and the threaded portion is not formed on a portion of the inner pin that is fitted into the recess. A planetary gear reduction device characterized by the above. In claim 6,
The screw portion is formed on the first support flange. A planetary gear reduction device according to the present invention. In any one of Claims 1 thru | or 7,
A planetary gear reduction device , wherein the shim has a hole through which the bolt can be inserted . Oite to any one of claims 1 to 8,
Two or more inner pins are provided,
The shim is sandwiched only between some of the two or more inner pins and the second support flange.
A planetary gear reduction device characterized by that .

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